TECHNICAL FIELD
[0001] The present invention relates to a method for manufacturing a mono cell in which
a sheet-like separator is disposed between sheet-like positive and negative electrodes.
BACKGROUND TECHNOLOGY
[0002] As one example of a radical unit formed by disposing a sheet-like separator between
a sheet-like positive electrode and a sheet-like negative electrode, one described
in a patent document 1 can be sited. In the radical unit of the patent document 1,
the bonding between the positive electrode and the separator and the bonding between
the negative electrode and the separator are carried out by disposing adhesive over
an bonding surface in, for example, a mesh shape.
[0003] In a state in which the adhesive is disposed in such a way, when viewed in the lamination
direction of the radical unit, a part at which the position of the adhesive between
the positive electrode and the separator overlaps the position of the adhesive between
the negative electrode and the separator, that is, a part at which adhesive is applied
to both sides of the separator exists. Therefore there is the fear that the thickness
of the radical unit becomes excessively large.
[0004] The present invention has been made in a consideration of such a problem, and an
object of the present invention is to provide a method for manufacturing a mono cell
with which an increase in the thickness of a mono cell caused by adhesive is suppressed.
PRIOR ART DOCUMENT
PATENT DOCUMENT
[0005] Patent Document 1: Japanese Patent Application Publication
2015-529957
SUMMARY OF THE INVENTION
[0006] The present invention is one in which, in a method for manufacturing a mono cell
in which a sheet-like separator is disposed between sheet-like positive and negative
electrodes, when viewed in a lamination direction of the mono cell, adhesives are
disposed such that adhesives on one surface of the separator do not overlap adhesives
on the other surface of the separator.
[0007] According to the present invention, the adhesives are not disposed at the same positions
on both of the surfaces of the separator, and consequently, the thickness of the mono
cell does not excessively increase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008]
FIG. 1 is a perspective view of an electrode lamination device of one embodiment.
FIG. 2 is a perspective view of a mono cell.
FIG. 3 is a side view of the mono cell.
FIG. 4 is an explanatory drawing of a sensor and a nozzle of a first dispenser.
FIG. 5 is an explanatory drawing showing disposing steps and applying positions of
adhesives by first, second and third dispensers.
MODE FOR IMPLEMENTING THE INVENTION
[0009] In the following, one embodiment of the present invention will be explained with
reference to the drawings.
[0010] In FIG. 1, an electrode lamination device 2 for manufacturing a mono cell (unit laminated
body) 1 is shown. For example, as shown in FIG. 2 and FIG. 3, a sheet-like negative
electrode 3 as an electrode, a sheet-like separator 4 and a sheet-like positive electrode
5 as an electrode are laminated in this order from a lower side, and by integrating
them, mono cell 1 is formed. Moreover, in the present embodiment, a sheet-like separator
6 is bonded onto positive electrode 5, and then mono cell 1 is formed to have a four-layer
structure. Negative electrode 3 is formed in a sheet-like state in such a manner that
slurry made by mixing active material, a conductive auxiliary agent, binder, an organic
solvent and the like is applied to both of the surfaces of current collecting foil,
such as copper foil, in a predetermined thickness, and then is dried. Similarly, positive
electrode 5 is formed in a sheet-like state in such a manner that slurry made by mixing
active material, a conductive auxiliary agent, binder, an organic solvent and the
like is applied to both of the surfaces of current collecting foil, such as aluminum
foil, in a predetermined thickness, and then is dried. The thickness of negative electrode
3 is thinner than that of positive electrode 5, and the size of negative electrode
3 is larger than that of positive electrode 5. As shown in FIG. 2, negative electrode
3 is cut so as to leave a tab portion 7. On the other hand, positive electrode 5 is
cut so as to leave a tab portion 8.
[0011] A rectangular electrode laminate (power generation element) is formed by laminating
a plurality of mono cells 1 formed in such a manner, and a lithium ion secondary battery
is formed by accommodating the electrode laminate in a laminate film exterior body
which is not shown in the drawings, together with electrolyte.
[0012] Separator 4 is substantially the same as separator 6, and has a function to hold
the electrolyte while suppressing the short circuit between positive electrode 5 and
negative electrode 3. For example, separators 4 and 6 are each made of a microporous
film of synthetic resin, such as polyethylene (PE) and polypropylene (PP), or nonwoven
fabric. In addition, separators 4 and 6 are each formed lager than negative electrode
3.
[0013] As shown in FIG. 1, separator 4 having a long continuous belt-like shape is centered,
and electrode lamination device 2 is provided with a pair of upper and lower conveyance
rollers 9, an absorption drum 10 for the negative electrode which is positioned on
the downstream side of conveyance rollers 9, a nip roller 11 positioned on the upper
side of this negative electrode absorption drum 10, an absorption drum 12 for the
positive electrode which is positioned on the downstream side of nip roller 11, and
a nip roller 13 positioned on the lower side of positive electrode absorption drum
12.
[0014] Conveyance rollers 9 are provided for conveying separator 4 along a conveyance direction
T.
[0015] Negative electrode absorption drum 10 is provided for absorbing sheet-like negative
electrode 3 which had been cut to a predetermined dimension and in which adhesives
14A, 14B and 14C had been disposed in a dot-like state by a first dispenser 15, and
superposing it to separator 4.
[0016] Nip roller 11 is provided for sticking negative electrode 3 on separator 4 by pressing
negative electrode 3 superposed to separator 4 to negative electrode absorption drum
10.
[0017] Positive electrode absorption drum 12 absorbs sheet-like positive electrode 5 which
had been cut to a predetermined dimension and in which adhesives 20A, 20B and 20C
had been disposed in a dot-like state by a second dispenser 21, and superposes it
to separator 4 so as to be arranged at a position corresponding to negative electrode
3.
[0018] Nip roller 13 is provided for sticking positive electrode 5 on separator 4 by pressing
negative electrode 3, separator 4 and positive electrode 5, which are superposed on
each other, to positive electrode absorption drum 12.
[0019] On the downstream side of nip roller 13, a third dispenser 26 is provided, and a
conveyance roller 29 positioned on the downstream side of third dispenser 26 is provided,
and a nip roller 40 positioned on the upper side of conveyance roller 29 is provided.
[0020] In a state in which negative electrode 3, separator 4 and positive electrode 5 are
superposed on each other, third dispenser 26 disposes adhesives 25A, 25B and 25C in
a dot-like state to positive electrode 5.
[0021] Conveyance roller 29 is provided for conveying negative electrode 3, separator 4
and positive electrode 5 superposed on each other and a separator 6 having a long
continuous belt-like shape, which is sent from the upper side of separator 4, along
conveyance direction T.
[0022] Nip roller 40 is provided for sticking separator 6 to positive electrode 5 by superposing
separator 6 on positive electrode 5 equipped with adhesives 25A, 25B and 25C and pressing
negative electrode 3, separator 4, positive electrode 5 and separator 6, which are
laminated, to conveyance roller 29.
[0023] A separator cutter 30 is provided on the downstream side of nip roller 40. Separator
cutter 30 is provided to cut separators 4 and 6 between adjacent two negative electrodes
3. By the cutting of separators 4 and 6, as shown in FIG. 2 and FIG. 3, a mono cell
1 in which negative electrode 3, separator 4, positive electrode 5 and separator 6
are integrated is formed.
[0024] In addition, in the present embodiment, conveyance direction T is a direction along
short sides of negative electrode 3 and positive electrode 5 having rectangular shapes
shown in FIG. 2. Each of tab portion 7 and tab portion 8 takes a posture directed
to the side with respect to conveyance direction T.
[0025] Here, for the convenience of the following explanation, the direction orthogonal
to conveyance direction T is defined as "width direction" of electrode lamination
device 2.
[0026] In addition, in the postures of negative electrode 3 and the like shown in FIG. 3,
the surface on the upper side of negative electrode 3 is defined as "upper surface
3a", and the surface on the lower side of negative electrode 3 is defined as "lower
surface 3b". In the same way, the surface on the upper side of separator 4 is defined
as "upper surface 4a", and the surface on the lower side of separator 4 is defined
as "lower surface 4b". In the same way, the surface on the upper side of positive
electrode 5 is defined as "upper surface 5a", and the surface on the lower side of
positive electrode 5 is defined as "lower surface 5b". In the same way, the surface
on the upper side of separator 6 is defined as "upper surface 6a", and the surface
on the lower side of separator 6 is defined as "lower surface 6b".
[0027] Moreover, regarding negative electrode 3, as shown in FIG. 5, with respect to conveyance
direction T, the edge portion of negative electrode 3 which becomes the downstream
side is defined as "front edge 31", the edge portion of negative electrode 3 which
becomes the upstream side is defined as "rear edge 32", the edge portion of negative
electrode 3 which becomes the right side is defined as "right edge 16", and the edge
portion (except tab portion 7) of negative electrode 3 which becomes the left side
is defined as "left edge 17". In the same way, regarding positive electrode 5, as
shown in FIG. 5, with respect to conveyance direction T, the edge portion of positive
electrode 5 which becomes the downstream side is defined as "front edge 33", the edge
portion of positive electrode 5 which becomes the upstream side is defined as "rear
edge 34", the edge portion of positive electrode 5 which becomes the right side is
defined as "right edge 27", and the edge portion (except tab portion 8) of positive
electrode 5 which becomes the left side is defined as "left edge 28".
[0028] As shown in FIG. 1, first dispenser 15 is provided at a position facing negative
electrode absorption drum 10, to bond upper surface 3a of negative electrode 3 to
lower surface 4b of separator 4. First dispenser 15 is provided with three nozzles
15A, 15B and 15C for respectively disposing (applying) adhesives 14A, 14B and 14C
in a dot-like state to part of upper surface 3a of negative electrode 3. Three nozzles
15A, 15B and 15C are configured in the substantially same manner, and they are provided
at predetermined intervals along width direction W. Here, regarding nozzles 15A and
15C positioned on both of the sides of first dispenser 15, nozzle 15A is provided
at a position at which adhesive 14A can be disposed to a position close to right edge
16 of negative electrode 3 with respect to conveyance direction T, and nozzle 15C
is provided at a position at which adhesive 14C can be disposed to a position close
to left edge 17 (except tab portion 7) (see FIG. 5) of negative electrode 3 with respect
to conveyance direction T.
[0029] Moreover, a sensor 19 for detecting a reference position 18 of negative electrode
3 (see FIG. 5) is provided on the upstream side of first dispenser 15. In the present
embodiment, reference position 18 of negative electrode 3 is the point at which front
edge 31 intersects right edge 16 of negative electrode 3 (see FIG. 5). In addition,
reference position 18 can be set to an arbitrary point on front edge 31. The detection
of reference position 18 by sensor 19 becomes a trigger for disposing the adhesives
from nozzles 15A, 15B and 15C of first dispenser 15 provided on the downstream side
of sensor 19. As shown in FIG. 4, when sensor 19 detects reference position 18 of
negative electrode 3 while negative electrode 3 moves, a signal for applying adhesives
14A, 14B and 14C is transmitted to first dispenser 15. Then, counting is started by
a timer which is not shown in the drawings based on the signal for the application,
and, after a predetermined time has elapsed, nozzles 15A, 15B and 15C of first dispenser
15 respectively dispose adhesives 14A, 14B and 14C in a dot-like state to upper surface
3a of negative electrode 3. Each of adhesives 14A, 14B and 14C from nozzles 15A, 15B
and 15C is disposed at a plurality of points (three points in the embodiment) along
conveyance direction T by using the counting of the timer.
[0030] In the same way, second dispenser 21 is provided at a position facing positive electrode
absorption drum 12, to bond lower surface 5b of positive electrode 5 to upper surface
4a of separator 4. Second dispenser 21 is provided with three nozzles 21A, 21B and
21C for respectively disposing adhesives 20A, 20B and 20C in a dot-like state to part
of lower surface 5b of positive electrode 5. Three nozzles 21A, 21B and 21C are configured
in the substantially same manner, and they are provided at predetermined intervals
along width direction W. Nozzle 21B positioned at the center of second dispenser 21
is provided at the same position as nozzle 15B positioned at the center of first dispenser
15 in the center in width direction W. On the other hand, nozzles 21A and 21C positioned
on both of the sides of second dispenser 21 are provided more inside in width direction
W than nozzles 15A and 15C positioned on both of the sides of first dispenser 15.
[0031] In addition, a sensor 24 for detecting a reference position 23 of positive electrode
5 (see FIG. 5) is provided on the upstream side of second dispenser 21. In the present
embodiment, reference position 23 is the point at which front edge 33 intersects right
edge 27 of positive electrode 5 (see FIG. 5). That is, reference position 23 of the
embodiment is positioned at the same corner as reference position 18, when viewed
in the lamination direction of mono cell 1. In addition, reference position 23 can
be set to an arbitrary point on front edge 33.
[0032] Moreover, third dispenser 26 is provided on the downstream side of positive electrode
absorption drum 12, to bond lower surface 6b of separator 6 to upper surface 5a of
positive electrode 5. Third dispenser 26 is provided with three nozzles 26A, 26B and
26C for respectively disposing adhesives 25A, 25B and 25C in a dot-like state to part
of upper surface 5a of positive electrode 5. Three nozzles 26A, 26B and 26C are configured
in the substantially same manner, and they are provided at predetermined intervals
along width direction W. Nozzle 26B positioned at the center of third dispenser 26
is provided at the same position as nozzle 15B positioned at the center of first dispenser
15 and nozzle 21B positioned at the center of second dispenser 21 in the center in
width direction W. On the other hand, regarding nozzles 26A and 26C positioned on
both sides of third dispenser 26, nozzle 26A is provided at a position at which adhesive
25A can be applied to a position closer to right edge 27 of positive electrode 5,
as compared with nozzle 15A, and nozzle 26C is provided at a position at which adhesive
25C can be applied to a position closer to left edge 28 (except tab portion 8) of
positive electrode 5, as compared with nozzle 15C.
[0033] In the same way as sensor 24 provided on the upstream side of second dispenser 21,
a sensor 37 for detecting reference position 23 of positive electrode 5 is provided
on the upstream side of third dispenser 26.
[0034] Next, with reference to FIG. 5, disposing steps and applying positions of adhesives
14A, 14B, 14C, 20A, 20B, 20C, 25A, 25B and 25C by the first, second and third dispensers
15, 21 and 26 will be explained. In FIG. 5, upper surface 3a of negative electrode
3 is bonded to lower surface 4b of separator 4 which is omitted in the drawing, and
lower surface 5b of positive electrode 5 is bonded to upper surface 4a of separator
4. Accordingly, positive electrode 5 whose size is smaller than that of negative electrode
3 is laminated on negative electrode 3 through separator 4, and when viewed in the
lamination direction of mono cell 1, the periphery of negative electrode 3 slightly
projects from the periphery of positive electrode 5, except the tab portions 7 and
8.
[0035] In FIG. 5, adhesives 14A, 14B and 14C of first dispenser 15 are each shown by a circle,
and adhesives 20A, 20B and 20C of second dispenser 21 are each shown by a circle having
dots thereinside. In addition, adhesives 25A, 25B and 25C of third dispenser 26 are
each shown by a circle having lattice pattern thereinside.
[0036] Moreover, in FIG. 5, there is shown the position in width direction W of each of
nozzles 15A, 15B and 15C (circles drawn by broken line), nozzle 21A, 21B and 21C (circles
drawn by alternate long and short dash line) and nozzles 26A, 26B and 26C (circles
drawn by alternate long and two short dashes line).
[0037] Here, for the convenience for the following explanation, the side toward front edges
31 and 33 is defined as "front side", and the side toward rear edges 32 and 34 is
defined as "rear side".
[0038] In the present embodiment, by nozzles 15A, 15B, 15C, 21A, 21B, 21C, 26A, 26B and
26C of the first, second and third dispensers 15, 21 and 26, adhesives 14A, 14B, 14C,
20A, 20B, 20C, 25A, 25B and 25C are each disposed three times in a dot-like state
along conveyance direction T. With this, each of dispenser 15, 21 and 26 applies a
total of nine adhesives.
[0039] First, by three nozzles 15A, 15B and 15C of first dispenser 15, adhesives 14A, 14B
and 14C are disposed in a dot-like state on upper surface 3a of negative electrode
3. At the time of the disposing, by nozzles 15A and 15C positioned on both of the
sides of first dispenser 15, adhesives 14A and 14C are disposed in a dot-like state
at positions near front edge 31 of negative electrode 3, and adhesives 14A and 14C
are disposed in a dot-like state at the center positions in conveyance direction T,
and, moreover, adhesives 14A and 14C are disposed in a dot-like state at positions
near rear edge 32 of negative electrode 3. After disposing adhesives 14A and 14C,
three adhesives 14A, 14A and 14A are arranged at equal intervals along conveyance
direction T at positions close to right edge 16, and three adhesives 14C, 14C and
14C are arranged at equal intervals along conveyance direction T at positions close
to left edge 17 (except tab portion 7). In addition, by nozzle 15B positioned at the
center of first dispenser 15, an adhesive 14B is disposed at front edge 31 of negative
electrode 3, and an adhesive 14B is disposed more on the front side than adhesives
14A and 14C disposed at the center in conveyance direction T by shifting applying
timing by adjusting a timer, and, moreover, an adhesive 14B is disposed near rear
edge 32 of negative electrode 3. After disposing adhesives 14B, in front edge 31 and
rear edge 32 sides, adhesives 14B are aligned with adhesives 14A and 14C along width
direction W, and in the center in conveyance direction T, adhesive 14B is provided
more on the front side than adhesives 14A and 14C.
[0040] Next, by three nozzles 21A, 21B and 21C of second dispenser 21, adhesives 20A, 20B
and 20C are disposed in a dot-like state on lower surface 5b of positive electrode
5. When adhesives 20A, 20B and 20C are disposed, adhesives 20A, 20B and 20C are disposed
at positions at which adhesives 20A, 20B and 20C do not overlap adhesives 14A, 14B
and 14C respectively. Specifically, regarding nozzle 21A and 21C disposed on both
of the sides of second dispenser 21, by providing nozzle 21A and 21C more on the inside
in width direction W than nozzle 15A and 15C disposed on both of the sides of first
dispenser 15, adhesives 20A and 20C are shifted more on the inside in width direction
W than adhesives 14A and 14C, and regarding nozzle 21B disposed in the center of second
dispenser 21, by adjusting the applying timing of adhesives 20B with a timer, adhesives
20B are shifted from adhesives 14B in conveyance direction T.
[0041] At the time of the disposing, by nozzles 21A and 21C positioned on both of the sides
of second dispenser 21, adhesives 20A and 20C are disposed in a dot-like state at
positions near front edge 33 of positive electrode 5, and adhesives 20A and 20C are
disposed in a dot-like state at the center positions in conveyance direction T, and,
moreover, adhesives 20A and 20C are disposed in a dot-like state at positions near
rear edge 34 of positive electrode 5. After disposing adhesives 20A and 20C, three
adhesives 20A, 20A and 20A are arranged at equal intervals along conveyance direction
T at positions more on the inner side in width direction W than adhesives 14A, 14A
and 14A, and three adhesives 20C, 20C and 20C are arranged at equal intervals along
conveyance direction T at positions more on the inner side in width direction W than
adhesives 14C, 14C and 14C. In addition, by nozzle 21B positioned at the center of
second dispenser 21, an adhesive 20B is disposed in a dot-like state at a position
more on the rear side than adhesive 14B on front edge 33 side, and an adhesive 20B
is disposed in a dot-like state at a position more on the rear side than adhesive
14B at the center in conveyance direction T, and, moreover, an adhesive 20B is disposed
in a dot-like state at a position more on the front side than adhesive 14B on rear
edge 34 side. After disposing adhesives 20B, three adhesives 20B, 20B and 20B are
shifted in conveyance direction T from the respective three adhesives 14B, 14B and
14B.
[0042] After disposing adhesives 20A, 20B and 20C by second dispenser 21, by three nozzles
26A, 26B and 26C of third dispenser 26, adhesives 25A, 25B and 25C are disposed in
a dot-like state on upper surface 5a of positive electrode 5. At the time of the disposing,
by nozzle 26B which is disposed at the center of third dispenser 26 and which is provided
at the same position as center nozzles 15B and 21B in width direction W, an adhesive
25B is disposed in a dot-like state at a position near front edge 33, and an adhesive
25B is disposed in a dot-like state at the center position in conveyance direction
T, and, moreover, an adhesive 25B is disposed in a dot-like state at a position near
rear edge 34. After disposing adhesives 25B, three adhesives 25B are arranged at equal
intervals along conveyance direction T. In addition, by nozzles 26A and 26C which
are positioned on both of the sides of third dispenser 26 and which are provided more
on the outside in width direction W than nozzles 15A and 15C on both of the sides
of first dispenser 15 respectively, adhesives 25A and 25C are disposed in a dot-like
state at positions near front edge 33, and adhesives 25A and 25C are disposed in a
dot-like state at the center positions in conveyance direction T, and, moreover, adhesives
25A and 25C are disposed in a dot-like state at positions near rear edge 34. After
disposing adhesives 25A and 25C, three adhesives 25A, 25A and 25A are arranged at
equal intervals along conveyance direction T at positions more on the outer side in
width direction W than adhesives 14A, 14A and 14A, and three adhesives 25C, 25C and
25C are arranged at equal intervals along conveyance direction T at positions more
on the outer side in width direction W than adhesives 14C, 14C and 14C. In addition,
three adhesives 25A, 25B and 25C are arranged at equal intervals in width direction
W at each of the positions near front edge 33, the center positions in conveyance
direction T and the positions near rear edge 34.
[0043] As the above, in the present embodiment, when viewed in the lamination direction
of mono cell 1, the positions of adhesives 14A 14B and 14C on lower surface 4b side
of separator 4 and the positions of adhesives 20A, 20B and 20C on upper surface 4a
side of separator 4 do not overlap each other. When viewed in the lamination direction
of mono cell 1, since adhesives 14A, 14B and 14C are not disposed at the same positions
as adhesives 20A 20B and 20C on both of the surfaces of separator 4, the thickness
of mono cell 1 does not excessively increase.
[0044] In addition, in the present embodiment, adhesives 14A and 14C disposed on negative
electrode 3 side are disposed more on the outer side in width direction W than adhesives
20A and 20C disposed on positive electrode 5 side. Since negative electrode 3 is formed
to be thinner than positive electrode 5, it tends to separate from separator 4 more
easily than positive electrode 5, and by disposing adhesives 14A and 14C disposed
on negative electrode 3 side on the outer side in that way, negative electrode 3 becomes
hard to separate from separator 4.
[0045] Moreover, in the present embodiment, although separator 6 is easily turned up by,
for example, wind because separator 6 is positioned on the uppermost side of mono
cell 1, since adhesives 25A and 25C are disposed on upper surface 5a of positive electrode
5 on the outermost side in width direction W to stick lower surface 6b of separator
6 on upper surface 5a of positive electrode 5, separator 6 can be surely stuck to
positive electrode 5.
[0046] In addition, in FIG. 5, although adhesive 14A and adhesive 25A, adhesive 14B and
adhesive 25B, adhesive 20B and adhesive 25B, and adhesive 14C and adhesive 25C are
partially overlapped with each other when viewed in the lamination direction of mono
cell 1, this occurs as a result of putting on emphases on making separation of negative
electrode 3 and separator 6, which are positioned on the outermost sided, hard.
[0047] In this way, in the present embodiment, adhesives 14A, 14B and 14C disposed on lower
surface 4b of separator 4 and adhesives 20A, 20B and 20C disposed on upper surface
4a of separator 4 do not overlap each other. Moreover, adhesives 25A, 25B and 25C
for bonding of separator 6 can be disposed at positions not overlapping them, if it
is necessary.
[0048] In addition, in the present embodiment, although, as shown in FIG. 1, one which linearly
conveys separator 4 has been described as an example, the configuration of a conveyance
line is not limited to the configuration shown in FIG. 1.
[0049] In addition, in the present embodiment, although mono cell 1 having a four-layer
structure formed of negative electrode 3, separator 4, positive electrode 5 and separator
6 has been described as an example, a mono cell having three-layer structure can be
applied to the present invention.